Examples of errors detected by the V780 diagnostic

V780. The object of non-passive (non-PDS) type cannot be used with the function.

Tizen

V780 The object 'my_voicedata' of a non-passive (non-PDS) type cannot be initialized using the memset function. ise-stt-mode.cpp 773

typedef struct _VoiceData VoiceData;

struct _VoiceData
{
  int voicefw_state;
  stt_h voicefw_handle;
  Evas_Object *naviframe;
  Evas_Object *layout_main;
  Evas_Object *progressbar;
  Evas_Object *scroller;
  Evas_Object *main_entry;
  Evas_Object *mic_button;
  SttStateVal state;
  char *kbd_lang;
  Ecore_Timer *start_timer;
  Ecore_Timer *refresh_timer;
  Ecore_Timer *progressbar_timer;
  Ecore_Timer *textblock_timer;
  Ecore_Timer *guide_text_timer;
  Ecore_Timer *btn_disabling_timer;
  Ecore_Timer *power_unlock_timer;
  Ecore_Timer *init_timer;

  std::vector<std::string> stt_results;                    // <=
  char *partial_result;
  int result_type;

  int disclaimer;

  is::stt::SttFeedback *sttfeedback;
  is::stt::SttManager *sttmanager;

  is::ui::WInputSttMicEffect *ieffect;
  is::ui::MicEffector *effector;
};

void show_voice_input(....)
{
  ....
  my_voicedata = (VoiceData*)malloc(sizeof(VoiceData));   // <=
  if (my_voicedata == NULL) {
    LOGD("%d::::Heap Overflow, ......!", __LINE__);
    return;
  }
  memset(my_voicedata, 0, sizeof(VoiceData));              // <=
  ....
}

void on_destroy(VoiceData *r_voicedata)
{
  ....
  VoiceData *voicedata = (VoiceData *)r_voicedata;
  ....
  free(voicedata);                                         // <=
}

An object is created by the malloc and memset functions and destroyed using the free function. The constructor for the object of the std::vector<std::string> is not called. Such an object cannot be used. The destructor is not called. At least there will be a memory leak. In general, there is no point in thinking how this code may work. There will be definitely undefined behavior.

Similar errors can be found in some other places:

• V780 The object 'my_voicedata' of a non-passive (non-PDS) type cannot be initialized using the memset function. w-input-stt-ise.cpp 51

DeepSpeech

V780 The object '& params' of a non-passive (non-PDS) type cannot be initialized using the memset function. binary_format.cc 261

/* Not the best numbering system,
   but it grew this way for historical reasons
 * and I want to preserve existing binary files. */
typedef enum
{
  PROBING=0,
  REST_PROBING=1,
  TRIE=2,
  QUANT_TRIE=3,
  ARRAY_TRIE=4,
  QUANT_ARRAY_TRIE=5
}
ModelType;

....

struct FixedWidthParameters {
  unsigned char order;
  float probing_multiplier;
  // What type of model is this?
  ModelType model_type;
  // Does the end of the file
  // have the actual strings in the vocabulary?
  bool has_vocabulary;
  unsigned int search_version;
};

....

// Parameters stored in the header of a binary file.
struct Parameters {
  FixedWidthParameters fixed;
  std::vector<uint64_t> counts;
};

....

void BinaryFormat::FinishFile(....)
{
  ....
  // header and vocab share the same mmap.
  Parameters params = Parameters();
  memset(&params, 0, sizeof(Parameters)); // <=
  ....
}

Godot Engine

V780 Instantiation of LocalVector < AnimationCompressionDataState >: The object 'w' of a non-passive (non-PDS) type cannot be copied using the memcpy function. local_vector.h 280

template <class T, class U = uint32_t,
          bool force_trivial = false, bool tight = false>
class LocalVector
{
  ....
public:
  operator Vector<T>() const
  {
    Vector<T> ret;
    ret.resize(size());
    T *w = ret.ptrw();
    memcpy(w, data, sizeof(T) * count); // <=
    return ret;
  }
  ....
  _FORCE_INLINE_ LocalVector(const LocalVector &p_from) { .... }
  ....
};

struct AnimationCompressionDataState
{
  uint32_t components = 3;
  LocalVector<uint8_t> data; // Committed packets.
  struct PacketData
  {
    int32_t data[3] = { 0, 0, 0 };
    uint32_t frame = 0;
  };

  float split_tolerance = 1.5;

  LocalVector<PacketData> temp_packets;

  // used for rollback if the new frame does not fit
  int32_t validated_packet_count = -1;
  ....
};

The class AnimationCompressionDataState contains an instance of LocalVector<uint8_t>, which has a non-trivial copy constructor. Therefore, AnimationCompressionDataState itself is non-trivially copyable. If the objects passed to memcpy are potentially-overlapping or not TriviallyCopyable, the behavior of 'memcpy' is not specified and may be undefined.

Similar errors can be found in some other places:

• V780 Instantiation of LocalVector < LocalVector <int> >: The object 'w' of a non-passive (non-PDS) type cannot be copied using the memcpy function. local_vector.h 280
• V780 Instantiation of LocalVector < Mapping, uint32_t, bool, bool >: The object 'w' of a non-passive (non-PDS) type cannot be copied using the memcpy function. local_vector.h 280
• V780 Instantiation of LocalVector < OAHashMap < uint64_t, Specialization > >: The object 'w' of a non-passive (non-PDS) type cannot be copied using the memcpy function. local_vector.h 280
• And 1 additional diagnostic messages.

Xenia

V780 The object 'out_info' of a non-passive (non-PDS) type cannot be initialized using the memset function. filesystem_win.cc 209

struct FileInfo
{
  enum class Type
  {
    kFile,
    kDirectory,
  };
  Type type;
  std::filesystem::path name;
  std::filesystem::path path;
  size_t total_size;
  uint64_t create_timestamp;
  uint64_t access_timestamp;
  uint64_t write_timestamp;
};

bool GetInfo(const std::filesystem::path& path, FileInfo* out_info)
{
  std::memset(out_info, 0, sizeof(FileInfo));                       // <=
  ....
  if (....) return false;
  /* fill 'out_info' data members */
  return true;
}

An object of the 'FileInfo' type is passed to the memset function as an argument. This type contains data members of the 'std::filesystem::path' type, which isn't trivially copyable. Using such data in the memset function may lead to undefined behavior.